Actually I guess the probe is always going to be playing catch-up with the air temperature. A true extreme will never be measured unless the probe is infinitely small or the temperature remains at exactly that extreme for a very long time (at least until the difference in temperature falls below the measurement error). That latter point might also affect the contention - measurement error was presumably much higher with mercury than modern probes. So I am no longer sure that I'd expect to see more extremes with modern equipment.

The move to AWS and the concurrent shift of many sites from Town Post Office to airports is like a fault line through the Australian climate records. In many cases the site change is not registered in the data because both have the same station number. This fault line is papered over by the analysis of the data using GIS procedures – any analysis is based on the stations reporting for that day/month and does not require a continuity of record at the site. Thus the ‘Australian’ daily maximum, and other BoM published analyses represents the available data interpolated to grid points and then areal averaging the gridpoints, not the data. For most practical purposes this is OK; the problems arise when trends or new records are claimed!

More at the comment by following the link above.

So the discontinuity/incompatability is subjected to a sponge-bath of hog-wash; to make it look like it's all been taken care of.

Keep washing those hogs. They've not yet been cleared for take-off.

It seems to me that the people "responsible" for managing the temperature dat have near-enough to no idea about how the data are obtained; or they don't care at all because they'll adjust them to fit their climate models anyway.